The object of this project is the elucidation of the biochemical mechanism of compensatory skeletal muscle hypertrophy. These studies will give greater insight into the physiological regulation of normal and pathologic skeletal muscle metabolism and into the role of the nervous system in this regulation. Present topics of investigation include: 1) The relationship between skeletal muscle and connective tissue in hypertrophy; 2) the relationship between compensatory skeletal muscle hypertrophy and endurance training; 3) localization of phosphoinositide changes in hypertrophy using radioautography; and 4) the relationship between stretch-induced hypertrophy and muscle protein synthesis and degradation. BIBLIOGRAPHIC REFERENCES: Jablecki, C., Dienstag, J. and Kaufman, S.: 3H-inositol incorporation into phosphatidyl-inositol in work-induced growth of rat muscle. Am. J. Physiol. 232: E324-329, 1977.